Technical Abstract:
The fungicidal activity of oleate towards yeasts isolated from carcasses of processed broilers was determined. Yeasts were isolated by blending skin from carcasses in peptone water, plating dilutions of the suspensions on acidified Potato Dextrose Agar, and incubating plates at room temperature for 3 d. Yeast isolates were identified as Yarrowia lipolytica, Cryptococcus terreus, and Candida ernobii using the MIDI Sherlock Microbial Identification System. The ability of different concentrations of oleate to reduce yeast populations was determined by mixing cultures of each yeast in 0, 2, 4, 6, 8, and 10% oleate solutions (w/v) for 5 min. Viable yeasts were enumerated on Sabouraud Dextrose Agar. The effect of contact time on the fungicidal activity of oleate was determined by mixing yeast cultures in 10% solutions of oleate for 10, 20, 30, 40, 50, or 60 min. At the end of each time period, viable yeasts were enumerated as previously described. Statistical analysis of results was performed using InStat 3.0. Findings indicated that significant reductions in the populations of Y. lipolytica, C. terreus, and C. ernobii occurred after mixing yeast in solutions of 4%, 6%, and 10% oleate, respectively. Furthermore, significantly fewer, Y. lipolytica, C. terreus, and C. ernobii were recovered after being mixed in 10% oleate solutions for 20 min or longer than from samples mixed for 10 min. In conclusion, oleate possesses fungicidal activity that significantly reduces populations of Y. lipolytica, C. terreus, and C. ernobii in vitro; therefore, washing carcasses in oleate solutions may reduce the number of fungi, as well as the number of bacteria associated with processed poultry.